June 25, 2015

We thought to write this little how-to guide since there appears to be many ideas on how to shrink AWS EC2 EBS volume for Linux but none discuss the Windows OS.

Scenario: You got an important instance that is using large amount of SSD or IO intensive disk on Amazon EC2 and you’d like to shrink the space used on these disks to save on costs.

Solution: To shrink or even completely change a root volume from SSD/IO based to Magnetic disk in few short steps:

a) In Windows, go to the Disk Management section and shrink the existing volume size (You can only shrink C:\ drive if it is the only volume on the Disk)

b) Create a new EBS volume using your preferred size and type, then attach this volume to the EC2 instance to be replaced. Then go into Windows Disk Management and bring online the new volume, then initialize it as MBR

d) Start Macrium Reflect Server and clone your already shrunk C:\ volume to the new EBS disk you’ve attached (note, the new disk must contain as much space or more than the C:\ volume TOTAL size) – Pay attention to clone the C:\ volume and the System Partition before it. Do not clone the unused space.

e) Once clone is completed successfully. Shutdown the instance, detach both EBS volumes from the instance. Then re-attach the new smaller volume to the instance as: /dev/sda1

Turn the Windows instance back on and verify connectivity. If all was done properly, your instance will come online with the new smaller sized volume.